Replace String.prototype.substr() occurrences with String.prototype.substring()

As outlined in https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/substr, which refers to the ECMA-262 specification, using the `substr` function is advised against.

Hence this PR, which replaces all remaining `substr` occurrences with `substring` instead. Please refer to https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/substr#Syntax respectively https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/substring#Syntax for the differences between the two functions.

Note that in most cases in the code-base there's only one argument passed to `substr`, and those require no other changes except replacing "substr" with "substring". For the other cases, the `substr(start, length)` calls are changed to `substring(start, start + length)` instead.

src/core/cff_parser.js

@@ -1366,7 +1366,7 @@ var CFFCompiler = (function CFFCompilerClosure() {
       nibbles += (nibbles.length & 1) ? 'f' : 'ff';
       var out = [30];
       for (i = 0, ii = nibbles.length; i < ii; i += 2) {
-        out.push(parseInt(nibbles.substr(i, 2), 16));
+        out.push(parseInt(nibbles.substring(i, i + 2), 16));
       }
       return out;
     },

src/core/cmap.js

@@ -228,7 +228,7 @@ class CMap {
     while (low <= high) {
       this._map[low++] = dstLow;
       // Only the last byte has to be incremented.
-      dstLow = dstLow.substr(0, lastByte) +
+      dstLow = dstLow.substring(0, lastByte) +
                String.fromCharCode(dstLow.charCodeAt(lastByte) + 1);
     }
   }

src/core/evaluator.js

@@ -2002,18 +2002,18 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
           switch (glyphName[0]) {
             case 'G': // Gxx glyph
               if (glyphName.length === 3) {
-                code = parseInt(glyphName.substr(1), 16);
+                code = parseInt(glyphName.substring(1), 16);
               }
               break;
             case 'g': // g00xx glyph
               if (glyphName.length === 5) {
-                code = parseInt(glyphName.substr(1), 16);
+                code = parseInt(glyphName.substring(1), 16);
               }
               break;
             case 'C': // Cddd glyph
             case 'c': // cddd glyph
               if (glyphName.length >= 3) {
-                code = +glyphName.substr(1);
+                code = +glyphName.substring(1);
               }
               break;
             default:

src/core/unicode.js

@@ -70,9 +70,9 @@ function getUnicodeForGlyph(name, glyphsUnicodeMap) {
     var nameLen = name.length, hexStr;
 
     if (nameLen === 7 && name[1] === 'n' && name[2] === 'i') { // 'uniXXXX'
-      hexStr = name.substr(3);
+      hexStr = name.substring(3);
     } else if (nameLen >= 5 && nameLen <= 7) { // 'uXXXX{XX}'
-      hexStr = name.substr(1);
+      hexStr = name.substring(1);
     } else {
       return -1;
     }

src/display/font_loader.js

@@ -195,8 +195,8 @@ if (typeof PDFJSDev === 'undefined' || !PDFJSDev.test('MOZCENTRAL')) {
       }
 
       function spliceString(s, offset, remove, insert) {
-        var chunk1 = s.substr(0, offset);
-        var chunk2 = s.substr(offset + remove);
+        var chunk1 = s.substring(0, offset);
+        var chunk2 = s.substring(offset + remove);
         return chunk1 + insert + chunk2;
       }
 

src/display/svg.js

@@ -373,7 +373,7 @@ SVGGraphics = (function SVGGraphicsClosure() {
     do {
       i--;
     } while (s[i] === '0');
-    return s.substr(0, s[i] === '.' ? i : i + 1);
+    return s.substring(0, s[i] === '.' ? i : i + 1);
   }
 
   /**